The present invention relates, in general, to combustors and incinerators, and more particularly to an improved incinerator structure which is designed to produce energy-efficient and pollution-free burning of organic fuels for the production of heat and the burning of waste materials for disposal of such materials.
Because of the growing recognition of and concern for the problems caused by burning organic fuels such as coal or waste materials which may include toxic chemicals or which may produce unpleasant or unsightly fumes and smoke as well as damaging exhaust gases, the development of an incinerator which is capable of producing complete combustion of such materials while emitting exhaust gases which meet or exceed government clean air standards is becoming of prime importance.
Extensive work and study, and large amounts of money, are being expended on the art and technique of combustion, and numerous advances have been made in the recent past. Many approaches to the design of incinerators have attacked the problem of incomplete combustion of waste materials through the use of large quantities of fuel, but this has lead to devices which are extremely wasteful by present standards, and such approaches are unsatisfactory in a time of declining fuel supplies. Thus, it is becoming necessary to develop incinerators that not only produce clean exhaust gases, but also are fuel-efficient standards which have in the past tended to be mutually exclusive. Similar problems are faced where the material to be burned is an organic fuel such as coal, where the primary purpose of the device is the production of heat rather than the disposal of waste material, for in such cases the clean air standards must still be met.
Since this is a highly developed field, and a wide variety of mechanical devices have been tried in an attempt to satisfy increasingly severe government standards, the prior art exemplifies the many diverse aproaches to combustion of waste material and organic fuels with each advance providing an improvement in a specified aspect of combustion devices. For example, the use of cyclonic flow in a furnace chamber is suggested in U.S. Patents such as No. 3,774,555 to Turner, and No. 3,792,670 to DiNozzi. These two patents, as well as Nos. 3,547,056 to Niessen and No. 3,870,676 to Hazzard et al disclose the use of afterburners in incinerators. A number of patents such as the Turner patent discussed above, and No. 3,706,445 to Gentry utilize a redundant flow where exhaust gases are used to heat incoming air while Patents such as No. 3,808,986 to Logdon suggest that by reflecting the heat produced through combustion within the furnace chamber can result in improved temperatures. Preheating of the inlet air is also suggested in U.S. Pat. No. 3,806,322 to Tabak.
In order to improve the mode of burning waste materials, some incinerators in the prior art operate on the batch process wherein a single load of waste material is placed in the incinerator, ignited and completely burned, after which a second load is placed in the incinerator and the process repeated. Examples of this procedure are illustrated in U.S. Pat. No. 3,491,707 to Bakker and 3,754,743 to Johnson. Another approach to the problem is illustrated in a large number of patents which utilize various conveyor means for carrying the materials through the furnace chamber of the incinerator in a continuous manner. An example of this is found in U.S. Pat. No. 3,924,548 to Chambon, wherein the waste material is fluidized by the inlet air flow and carried thereby through the incinerator. Other examples are found in U.S. Pat. Nos. 2,024,652 to Martel, 3,861,331 to Saitoh, et al, and 3,871,286 to Henriksen, all of which show various conveyor arrangements.
As illustrated by the foregoing patents, the art has approached the problems of combustion on a piecemeal basis, adding various features to existing devices and producing more and more complex and thus more expensive incinerators, without solving the dual problems of a pollutionfree exhaust and fuel efficiency.